In the garden: Many flowers
On Crops: Beans, cucumbers, peppers, tomatoes, potatoes, corn and strawberries
Temperate and subtropical climates worldwide
Closely related to spiders, spider mites (sometimes called web-spinning mites) are specialists at colonizing drought-stressed plants. Under warm, dry conditions with temperatures above 80°F (26 °C), leaves become stippled with hundreds of tiny yellow dots that run together to make the leaves look sun-bleached. On leaf undersides, a faint webbing is often present, especially near the leaf tips.
Spider mites use piercing mouthparts to suck juices from plants. Heavily infested plants are weakened by spider mite feeding. Spider mites are attracted to drought-stressed plants.
Spider mites thrive under hot, dusty conditions, so keeping the garden watered helps prevent problems. Spider mites also have numerous natural enemies that are easily wiped out by the use of pesticides. In organic gardens where beneficial insects are encouraged, spider mite problems are rare.
Clip off and compost heavily infested leaves, because they will not recover. Thoroughly spray the plants with a fine spray of water, taking care to rinse leaf undersides. If the mites persist, repeat the water spray and then cover plants with an old sheet or other lightweight cloth for a couple of days. Shade and moist, cool conditions will seriously set back spider mites. To save a prized plant, an oil-based fungicide such as neem oil is the best intervention.
If you tap an infested leaf over a white sheet of paper, a 10x magnifying glass will reveal numerous moving specks, which are the spider mites.